Automatic balance adjusting centrifugal apparatus

ABSTRACT

A centrifugal machine of automatic balance type is provided for detecting an unbalance in a specimen mounted on a rotor lever before every centrifugal machining, and for moving horizontally the rotor lever according to detected results, maintaining automatic balance, thereby preventing destruction of a specimen due to an unbalance of the rotor, and extending the life of the machine.

TECHNICAL FIELD

The present invention relates to a centrifugal machine of automaticbalance type, and particularly to a centrifugal machine of automaticbalance type for detecting a load unbalance between specimens mounted ona rotor lever and for moving horizontally the rotor lever itself or abalance weight member according to detected results, thereby maintainingan automatic balance before every centrifugal machining.

BACKGROUND ART

Generally, a centrifugal machine is an apparatus for rotating a rotorcontaining a specimen in high speed, giving the specimen highcentrifugal acceleration, so that a specimen of high density ispositioned on an outer layer in a radial direction while a specimen oflow density is positioned on an inner layer in a radical direction,thereby separating an ingredient thereof

FIG. 1 is a cross-sectional view schematically representing a relatedcentrifugal machine of automatic balance type. As shown in FIG. 1, arelated centrifugal machine of automatic balance type is comprised of: abase 2 installed within an outer case 1; a spring 5 installed between abracket 4 and the base 2 to which a diving motor 3 is mounted, forsupporting a rotational part consisting of the diving motor 3 and arotor, etc. Furthermore, the spring 5 has an indented rubber tube 6 onits outer periphery, so that spring function and attenuation functionare provided by means of such spring 5 and rubber tube 6.

In the meantime, a rotor 8 is mounted on an upper portion of arotational shaft 7 which is supported by a shaft pad in the bracket 4,for free rotation. As a bottom of the rotational shaft 7 is connected toa motor shaft, torque of the driving motor 3 is transferred to the rotor8. A bucket 9 for accommodating a specimen is mounted on the rotor 8 sothat it rotates freely by means of a pin 10. A balancer body 20 ofcylindrical shape is fixed on a male screw 11 extended from therotational shaft 7 in the upper portion of the rotor 8, and a ball 21 iscontained within such balancer body 20. In the picture, referencenumerals 12, 13, 15 represent a chamber, a chamber door, an unbalancemess, respectively.

The related centrifugal machine of automatic balance type having aconstitution as mentioned above, adjusts a ratio of a ball 21 radius toa radius of the cylinder constituting the balancer body 20, distancebetween a center of the cylinder and a center of rotation, and relationbetween a concave groove within the cylinder and a half width, therebycorrecting unbalance due to a load difference between specimenscontained in the bucket 9. More details are described in JapaneseLaid-Open Application No. 11-262683 (publication date: Sep. 28, 1999).Accordingly, description thereof is omitted.

According to the foregoing related centrifugal machine of automaticbalance type, an unbalance generated from a load difference betweenspecimens that is within a predetermined range can be correctedautomatically, but in case of centrifugal machining a specimen beyondsuch range, a problem that there is no safety device for protecting aspecimen and a centrifugal machine. In other words, whenever using acentrifugal machine, a user should determine whether there is a problemin operating the machine before using the machine. If a user does notpay a proper attention like this, an excessive vibration may begenerated in a rotational shaft and a specimen is destroyed, and inworst case, a bearing and a driving part including a motor may be brokendown, so that life of a centrifugal machine is reduced

DISCLOSURE OF THE INVENTION

The present invention has been made to solve the above mentionedproblems and, therefore, it is an object of the present invention toprovide a centrifugal machine of automatic balance type for detecting anunbalance in a specimen mounted on a rotor lever before everycentrifugal machining, and for moving horizontally the rotor leveritself or a balance weight member according to detected results,maintaining an automatic balance, thereby preventing destruction of aspecimen due to an unbalance of the rotor and extending life of themachine.

It is another object of the present invention to provide a centrifugalmachine of automatic balance type for displaying a status ofimpossibility that automatic balance condition is not maintained due toa severe load unbalance so that a user recognizes the status, therebypreventing destruction of a specimen and extending life of the machine.

According to an aspect of the invention to achieve the above objects ofthe present invention, it is provided a centrifugal machine of automaticbalance type comprising: more than one rotor lever, to both ends ofwhich a specimen is hooked; a rotor for supporting the rotor lever sothat it moves horizontally; a lever moving means mounted within therotor, for moving horizontally the rotor lever an central line ofrotation of the rotor; a load detecting means for detecting loadsweighed on both the ends of the rotor lever, a centrifugal motor forrotating the rotor; an electrical connection means for connecting ordisconnecting the load detecting means and the lever moving means to andfrom an external electrical circuit of the rotor, and a controllingmeans for controlling the electrical connection means so as to connectelectrically the external electrical circuit to the load detecting meansand the lever moving means, for calculating loads weighed on both theends of the rotor lever by means of a detected signal provided from theload detecting means, and for controlling the lever moving means so thatcentrifugal forces exerted on both the ends of the rotor lever reach abalance.

In the foregoing constitution, the load detecting means may be comprisedof a strain gauge or a pressure sensor. Also, the lever moving means maybe comprised of a lever moving motor; a worm connected to the levermoving motor in an axial combining manner; a worm wheel engaged with theworm; a pinion connected to the worm wheel in a coaxial combiningmanner, and a rack formed lengthwise on the rotor lever, engaged withthe pinion.

In the meantime, in case that the rotor lever is two, an intersectingconcave groove of a width greater than a width of the rotor lever isformed on an intersecting portion so that rotational plane of each rotorlever lies on the same plane, and the lever moving means may beinstalled in an upper housing and a lower housing of the rotor,respectively.

The electrical connection means may be comprised of a wiring layerexposed to the rotational shaft of the rotor, with electricallyconnected to the load detecting means and the lever moving means; awiring contact plate for coming in contact with the wiring layer onlywhen an external force is applied; and a solenoid for applying orremoving an external force to the wiring contact plate.

Furthermore, the electrical connection means is further comprised of adisplaying means for giving a warning in case that a load differencebetween both ends of the rotor lever exceeds a predetermined value. Incase that the load difference exceeds the predetermined value as aresult of the load calculation, the controlling means controls to drivethe displaying means, thereby preventing centrifugal machining underinadequate condition of excess load difference.

According to another aspect of the present invention, it is provided acentrifugal machine of automatic balance type comprising: more than onerotor lever, on both ends of which a specimen is mounted; a rotor towhich the rotor lever is fixed; a balance weight member installed on acenter portion of the rotor lever, for being able to move horizontally;a weight member moving means mounted within the rotor, for movinghorizontally the balance weight member on a central line of rotation ofthe rotor; a load detecting means installed on the rotor lever, fordetecting loads weighed on both the ends of the rotor lever; acentrifugal motor for rotating the rotor; an electrical connection meansfor connecting or disconnecting the load detecting means and the weightmember moving means to and from an external electrical circuit of therotor; and a controlling means for controlling the electrical connectionmeans so as to connect electrically the external electrical circuit tothe load detecting means and the weight member moving means, forcalculating loads weighed on both the ends of the rotor lever by meansof a detected signal provided from the load detecting means, and forcontrolling the weight member moving means so that centrifugal forcesexerted on both the ends of the rotor lever reach a balance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view schematically showing a relatedcentrifugal machine of automatic balance type;

FIG. 2 is a perspective view schematically showing appearance of acentrifugal machine of automatic balance type according to oneembodiment of the present invention;

FIG. 3 is a cross-sectional view for a rotor, taken along line 3—3 ofFIG. 2;

FIG. 4 is a cross-sectional view for a rotor, taken along line 4—4 ofFIG. 2;

FIG. 5 is a top, plan view for a rotor lever shown in FIG. 3;

FIG. 6 is a block diagram illustrating electrical constitution for acentrifugal machine of automatic balance type according to the presentinvention;

FIG. 7 is a perspective view schematically showing appearance of acentrifugal machine of automatic balance type according to anotherembodiment of the present invention;

FIG. 8 is an exploded, perspective view for a rotor seen from upper sidewith some parts removed in FIG. 7;

FIG. 9 is an exploded, perspective view for a rotor seen from bottomside with some parts removed in FIG. 7;

FIG. 10 is a cross-sectional view for a rotor, taken along line 10—10 ofFIG. 8; and

FIG. 11 is an exploded, perspective view for a rotor seen from upperside with some parts of a centrifugal machine of automatic balance typeaccording to the present invention taken out.

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of a centrifugal machine of automatic balancetype according to the present invention will now be described withreference to the accompanying drawings. The matters defined in thedescription such as a detailed construction and elements of a circuitare nothing but the ones provided to assist in a comprehensiveunderstanding of the invention. Thus, it is apparent that the presentinvention can be carried out not limited to those defined matters. Also,well-known functions or constructions are not described in detail sincethey would obscure the invention in unnecessary detail.

FIG. 2 is a perspective view schematically showing appearance of acentrifugal machine of automatic balance type according to oneembodiment of the present invention, taking an example where two rotorlevers are adopted. As shown in FIG. 2, a centrifugal machine ofautomatic balance type according to one embodiment of the presentinvention is roughly comprised of a base 100; a centrifugal motor 120supported by the base 100; a rotor 200 connected to the centrifugalmotor in an axial combining manner and equipped with rotor levers230,240; a wiring contact plate 130 for connecting with an electricalcircuit part in an inside of the rotor 200; and a solenoid 140 forattaching to or being detached from the wiring contact plate 130.

In the foregoing constitution, a plurality of vibration absorbingmembers 110 is installed between an upper plate 124 of the centrifugalmotor 120 and the base 100, so that the centrifugal motor 120 is hung bythe vibration absorbing members 110 and supported accordingly. Vibrationgenerated upon centrifugal machining is absorbed and attenuated by suchvibration absorbing members 10. The vibration absorbing member 110 maybe, for example, comprised of a spring and a rubber tube inserted on anouter periphery of the spring as illustrated in a centrifugal machine ofFIG. 1.

In the meantime, a motor shaft 122 of the centrifugal motor 120 and arotational shaft (not shown) of the rotor 200, for example, are combinedby means of a flexible coupling 150 such as an universal joint (notshown). Also, on a appropriate position in the rotational shaft of therotor, for example, on an upper periphery of the flexible coupling 150,a slip ring 160 is installed, where a wiring layer (not shown) connectedto the electrical circuit part in the inside of the rotor 200 isarranged and exposed. By such structure of the slip ring 160, anelectrical wiring in and outside of the rotor 200 can be touched andseparated without being twisted. For a base layer of the slip ring 160,durable insulating material such as tetron, vinyl chloride, ceramic orsilicon may be used. Metallic wiring layers are arranged up and down asmany as necessary, forming cocentric circles on such base layer (Referto FIG. 3).

In the meantime, the rotor 200 is configured such that two rotor levers230 and 240 lie at right angles each other in insides of an upperhousing 210 and a lower housing 220. For such configuration, forexample, four lever guiding holes 222 and 224 intersectingperpendicularly each other are formed on an outer periphery of the lowerhousing 220, and the rotor levers 230 and 240 are moved horizontally forbalance maintenance, with passing through and being inserted to thelever guiding holes 222 and 224.

Reference numerals 232 and 242 in the picture represent a hookingportion, respectively, formed on both the ends of the rotor lever 230and 240, to which a bucket (not shown) containing a specimen is hookedand reference numerals 236,246 represent a strain gauge stuck on maximumbending stress point in both the ends of the respective rotor lever 230and 240, for detecting unbalance in loads weighed on both the ends ofthe rotor lever 230 and 240. A plurality of strain gauges 236 and 246may be installed on one end of the respective rotor lever 230 and 240.

In such structure, when strain is generated on both the ends ofrespective rotor lever 230 and 240 due to mounting of the bucket (notshown) containing a specimen, resistance value of a metal resistancewire in the strain gauges 236 and 246 stuck on the respective rotorlever, begin to change. Therefore, when voltage is applied on the straingauge 236 and 246, voltage change is obtained in proportional toresistance change of the strain gauge 236 and 246 which corresponds tothe strain generated in the rotor lever 230 and 240 and load differenceof a specimen weighed on both the ends of the rotor 230 and 240 could bedetected by amplification of the above voltage change.

In the meantime, the wiring contact plate 130 is configured such that itcomes into one-to-one contact with the wiring layer formed on the slipring 160. When external force by a push rod 142 in an end of thesolenoid 140 is not applied, the wiring contact plate 130 remainsisolated from the wiring layer by a spring (not shown) of less elasticforce than the external force by the push rod 142. But, when externalforce by the push rod 142 is applied on the wiring contact plate 130,the wiring contact plate 130 comes into contact with the wiring layer, adetecting signal from the electrical circuit part in the inside of therotor 200 is transmitted to a controlling part described below, andcommand from the controlling part is transmitted to the electricalcircuit part in the inside of the rotor 200.

FIG. 3 is a cross-sectional view for a rotor, taken along line A—A ofFIG. 2 and FIG. 4 is a cross-sectional view for a rotor, taken alongline B—B of FIG. 2, and FIG. 5 is a top, plan view for a rotor levershown in FIG. 3. As shown in FIG. 3 through FIG. 5, two rotor levers 230and 240 lie at right angles each other, across the lever guiding holes222 and 224 of the lower housing 220, and in order to save space,intersecting concave grooves 234 and 244 facing each other are formedrespectively in an intersecting portion of the two rotor lever 230 and240 upon installation. Namely, one rotor lever 230 (called an upperrotor lever in order for easy discrimination hereinafter) has theconcave groove 234 in its lower side and the other rotor lever 240(called an lower rotor lever hereinafter) has the concave groove 244 inits upper side. Further, a width of the respective intersecting groove234 and 244 should be appropriately wider than that of the respectiverotor lever 230 and 240, for allowing horizontal movement of the upperrotor lever 230 and the lower rotor lever 240. The upper rotor lever 230has a rack 238 on its upper side as shown in FIG. 5.

A motor assembly 250 and a gear box 260 for moving horizontally theupper rotor lever 230 could be installed in an inside of the upperhousing 210. First of all, the motor assembly 250 could be comprised ofa lever moving motor 252 and a supporting bracket 254. Morespecifically, the motor assembly 250 is fixed in the upper housing bythe supporting bracket 254 so that a motor shaft 252 a may be positioneddownward from the central line of rotation of the rotor 200.

The gear box 260 is comprised of a worm 262 connected to the motor shaft252 a and a worm wheel 264 engaged with the worm 262 by an appropriategear ratio, and pinion 266 is installed on the same axel of the wormwheel 264, leaving predetermined interval. Such pinion 266 is engagedwith the rack 238 on the upper rotor lever 230. Like the foregoingconstitution, by adopting the worm 262 and the worm wheel 264, the wormwheel 264 cannot rotate the worm 262, whereby unwanted movement of therotor lever 230 by centrifugal force due to high speed rotation of therotor 200, could be prevented.

In the meantime, a motor assembly 270 and a gear box 280 for movinghorizontally the lower rotor lever 240 could be installed in an insideof the lower housing 220. First of all, the motor assembly 270 could becomprised of a lever moving motor 272 and a supporting bracket 274. Morespecifically, the motor assembly 270 is fixed in the lower housing bythe supporting bracket 274 so that a motor shaft 272 a may be positionedupward from the central line of rotation of the rotor 200.

The gear box 280 is comprised of a worm 282 connected to the motor shaft272 a and a worm wheel 284 engaged with the worm 282 by an appropriategear ratio, and pinion 286 is installed on the same axel of the wormwheel 284, leaving predetermined interval. Such pinion 286 is engagedwith the rack (not shown) formed on an lower side of the lower rotorlever 240.

Reference numerals 252 b and 272 b in FIG. 3 through FIG. 5 represent apower supply terminal of the lever moving motor 252 and 272, referencenumerals 261 and 281 represent a supporting bracket for the gear box280, and reference numerals 268 and 288 represent a shaft pin installedon the respective supporting bracket 261 and 281, for rotating with therespective worm wheel 264 and 284 and respective pinion 266 and 286mounted on the shaft. Reference numeral 170 represents a combining pin170 for combing the rotational shaft connected by the centrifugal motor120, more specifically, the centrifugal motor 120 and the flexiblecoupling 150, with the rotor 200 and the reference numeral 162represents a wiring layer formed on the slip ring 160.

FIG. 6 is a block diagram illustrating electrical constitution for acentrifugal machine of automatic balance type according to the presentinvention. As shown in FIG. 6, electrical constitution for a centrifugalmachine of automatic balance type according to the present invention iscomprised of a key inputting part 310 for selecting and receivingvarious functions provided to the machine; a balance detecting part 312having the strain gauges 236 and 246 and neighboring circuit elements,for detecting balance state of specimen loads weighed on both the endsof the rotor levers 230 and 240; a centrifugal separation driving part318 for driving the centrifugal motor 120, rotating the rotor 200; levermoving parts 320 and 322 for driving the lever moving motors 252 and272, moving horizontally the rotor levers 230 and 240; a contact pointattaching, detaching part 324 for establishing electrical system fordriving the solenoid 140 so that the wiring contact plate 130 comes intocontact with the wiring layer 162, thereby receiving a detected signalfrom the balance detecting part 312, delivering a control command to thelever moving part 320 and 322; and a controlling part 300 forcontrolling overall operation of the machine.

In the foregoing constitution, for the lever moving motors 252 and 272,stepping motor in which precise control for a rotational angle ispossible could be used and servo motor also could be used. Further, aformula for computing a moving distance of the rotor lever 230,240 basedon a rotational angle of the lever moving motors 252 and 272, and amoving distance based on a load difference for a centrifugal forcebalance, is contained in the controlling part 300(Refer to amathematical formula 1 described below). Reference numeral 314 in thepicture, represents a displaying part for giving a user a warning incase that an unbalance of a specimen load is too remarkable to beovercome by the present invention.

Operation for a centrifugal machine of automatic balance type accordingto the present invention, will now be described herein below in detail.

First of all, when a user inputs a balance detecting function by meansof the key inputting part 310 while mounting a bucket containing aspecimen at hooking portions 232 and 242 of the rotor levers 230 and240, the controlling part 300 receives this input, then gives a commandto the contact point attaching, detaching part 324, driving the solenoid140, thereby bringing the wiring contact plate 130 into contact with thewiring layer 162. After that, the balance detecting part 312 transmitsdetected results of the strain gauges 236 and 246 to the controllingpart. 300 via the wiring layer 162 and the wiring contact plate 130, andthe controlling part 300 receives this results, computing an unbalanceamount between both the ends of the respective rotor lever 230 and 240and an horizontal moving amount of the rotor lever 230 and 240 based onthe unbalance amount, using the following formulae, then giving a movingcommand to the lever moving part 320 and 322 for achieving a balance incentrifugal force.

Formula 1f ₁ =m ₁ r ₁ω²Formula 2f ₂ =m ₂ r ₂ω²

Here, f₁ and m₁ represent centrifugal force and the total load ofspecimens weighed on one end of either rotor lever 230, respectively,while f₂ and m₂ represent centrifugal force and the total load ofspecimens weighed on the other end of the same rotor lever 230. Further,r₁ and r₂ represent a distance between a rotational center and aspecimen, respectively, and ω represents angular velocity. The foregoingis true of the other rotor lever 240.

From the above two mathematical formulae, a formula 3 for movinghorizontally the rotor lever is derived as follows.

Formula 3m ₁ r ₁ =m ₂ r ₂

In the meantime, upon completion of moving the rotor lever 230 and 240,namely, when a balance is maintained, the controlling part 300 gives acommand to the contact point attaching, detaching part 324 so as toretreat the push rod 142 of the solenoid 140, thereby isolating thewiring contact plate 130 from the wiring layer 162. At this state, thecontrolling part 300 drives the centrifugal motor 120, therebyperforming centrifugal separation with the balance maintained.

FIG. 7 is a perspective view schematically showing appearance of acentrifugal machine of automatic balance type according to anotherembodiment of the present invention, in which an example adopting onerotor lever is shown. FIG. 8 is an exploded, perspective view for arotor seen from upper side with some parts removed in FIG. 7, and FIG. 9is an exploded, perspective view for a rotor seen from bottom side withsome parts removed in FIG. 7, and FIG. 10 is a cross-sectional view fora rotor, taken along line C—C of FIG. 8.

As illustrated in FIG. 7 through FIG. 10, a centrifugal machine ofautomatic balance type according to another embodiment of the presentinvention is roughly comprised of a base 500; a centrifugal motor 520supported by the base 500; a rotor 600 having a rotor lever 630,connected to the centrifugal motor 520 in an axial combining manner; awiring contact plate 630 for connecting with an electrical circuit partin an inside of the rotor 600; and a solenoid 640 for attaching anddetaching the wiring contact plate 630.

In the foregoing constitution, a plurality of vibration absorbingmembers 510 is installed between an upper plate 524 of the centrifugalmotor 520 and the base 500, so that the centrifugal motor 520 is hung bythe vibration absorbing members 510 and supported accordingly. Vibrationgenerated upon centrifugal machining is absorbed and attenuated by suchvibration absorbing members 510.

On an upper periphery of a motor shaft 522, a slip ring 560 is installedwhere the wiring layer (not shown) connected to the electrical circuitpart in the inside of the rotor 600 is arranged and exposed. By suchstructure of the slip ring 560, an electrical wiring in and outside ofthe rotor 600 can be touched and separated without being twisted.

In the meantime, the rotor 600 is configured such that one rotor lever630 is installed in insides of an upper housing 610 and a lower housing620. But, as the present embodiment adopts a pressure sensor of directapplication type 690 (FIG. 8) for use as a load detecting means, therotor lever 630 is comprised of separate assemblies, not single memberas the embodiment shown in FIG. 2. Namely, the rotor lever 630 iscomprised of a lever central body 636 positioned on a central portion,and two rotational arms 632 connected to both ends of such lever centralbody 636 by means of a hinge 638, for rotating up and down. Therotational arm 632 on both the ends of the lever central body 636, hasthe pressure sensor 690 in its lower portion for detecting a pressure ofthe rotational arm 632 in a direct application manner, and eachrotational arm 632 maintains balanced horizontal state by support ofsuch pressure sensor 690. Reference numeral 692 (FIG. 10) represents apressure applying ball for distributing uniformly a pressure from therotational arm 632, to a pressure receiving portion of the pressuresensor 690.

On oppositely faced portions of an upper housing 610 and a lower housing620, two lever guiding cavities 622 are formed. The rotor lever 630 ismoved horizontally for balance maintenance, with passing through andbeing inserted to the lever guiding cavities 622. Reference numeral 634(FIG. 8) represents a hooking protuberance formed on both the ends ofthe rotor lever 630, for combining with a bucket 700 containing aspecimen 710 so that the bucket 700 could rotate.

With such constitution, when a difference is generated betweenmeasurement values of the pressure sensor 690 in both sides with aspecimen mounted on the bucket 700, such difference is detected by thebalance detecting part 312, provided to the controlling part 300 shownin FIG. 6, where a load difference between the specimens weighed on boththe ends of the rotor lever 630 is calculated, and the rotor lever 630is moved horizontally according to calculation results thereto, wherebya balance is maintained.

A motor assembly 650 (FIG. 9) for moving horizontally the rotor lever630, could be installed in an inside of the upper housing 610. First ofall, the motor assembly 650 could be comprised of a lever moving motor652 and a supporting bracket 654. More specifically, the motor assembly650 is fixed in the upper housing by the supporting bracket 654 so thata motor shaft 652 a may be positioned downward from the central line ofrotation of the rotor 600.

A worm 662 is connected to the motor shaft 652 a in an axial combiningmanner, then a worm wheel 664 is engaged with the worm 662 by anappropriate gear ratio, and pinion 666 is installed on the same axel ofthe worm wheel 664, leaving predetermined interval, then the pinion 666is engaged with the rack 636 a formed on the upper side of the levercentral body 636. Like the foregoing, by adopting the worm 662 and theworm wheel 664, the worm wheel 664 cannot rotate the worm 662, wherebyunwanted movement of the rotor lever 630 by centrifugal force due tohigh speed rotation of the rotor 600, could be prevented.

The reference numeral 652 b represents a power supply terminal of thelever moving motor 652, and 668 represents a shaft pin installed on thesupporting bracket 661, for rotating with the worm wheel 664 and pinion666 mounted on the shaft.

FIG. 11 is an exploded, perspective view for a rotor seen from upperside with some parts of a centrifugal machine of automatic balance typeaccording to the present invention taken out, and the same referencenumerals are given to the same constituents as those shown in FIG. 8,detailed description thereto is omitted. As shown in FIG. 11, thepresent embodiment maintains an automatic balance by moving horizontallya balance weight member 680 which forms a separate body from the rotorlever 630′ instead of moving the rotor lever itself 630′. Though notshown in the picture, the present embodiment could have the sameconstitution in the rest parts as the constitution of the embodimentshown in FIG. 7 through FIG. 10, with difference only in theconstitution related to the above separate balance weight member 680.

In the meantime, for such configuration, the present invention iscomprised of a rotor lever 630′ being fixed in the rotor (not shown); amoving guiding groove 636′b being formed, in parallel with both therotational arms 632, on the lever central body 636′; a balance weightmember 680 of, for example, a rectangular shaped stick being insertedinto such moving guiding groove 636 b′. Further, a rack 682 is formed onthe upper side of the balance weight member 680, for moving horizontallythe balance weight member 680 within the moving guiding groove 636′b,and a pinion 666 is engaged with such rack 682.

Reference numeral 636′c represents a bolt fastening bole to which a boltfor fixing the rotor lever 630′ in the rotor is fastened. Preferably,the bolt fastening hole 636′c is formed lest the fastened bolt should beprojected from a bottom side of the moving guiding groove 636′b.

With such constitution, when a difference is generated betweenmeasurement values of the pressure sensor 690 in both sides withspecimens mounted on the bucket 700, such difference is detected by thebalance detecting part 312, then provided to the controlling part 300shown in FIG. 6. After that, the controlling part 300 calculates a loaddifference between the specimens weighed on both the ends of the rotorlever 630′, using a detected signal provided from the balance detectingpart 312, then calculating moving distance necessary according to abovecalculation results, moving horizontally the balance weight member 680in a predetermined direction as necessary amount, thereby maintaining anautomatic balance.

Formula 4m ₁ r+dmΔr=m ₂ r−dmΔr

In the above mathematical formula 4, m₁, m₂ represent loads weighed onboth the rotational arms 632 of the rotor lever 630′, respectively, rrepresents a rotational radius of the each rotational arm 632, dmrepresents a mess of the balance weight member 680, and Δr represents amoving distance of the balance weight member 680.

To achieve the foregoing, the controlling part 300 could determine amoving distance (Δr) with reference to a table stored in its selfcontained memory, regarding a moving direction and distance of thebalance weight member 680 according to a difference in measurementvalues of pressure sensors in both the sides, or could determine amoving distance (Δr) by calculating directly a moving direction andmoving distance using the formula 4.

In the meantime, according to the present embodiment, the lever movingpart 320 will be changed to a weight member moving part in its name.

Though the invention has been shown and described with reference to acertain preferred embodiment thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

For example, contrary to the embodiment mentioned above, three or morerotor levers could be installed. Further, a load difference could bedetected by a rod cell stuck on appropriate portion of both the ends ofthe rotor lever, and the wiring layer could be installed on otherportion, not the slip ring, for example on a periphery of the upperhousing or the lower housing, or a surface of an upper side of the upperhousing. Also, instead of the worm and worm wheel for moving the rotorlever, a bevel gear or other kind of gear could be adopted.

INDUSTRIAL APPLICABILITY

As described in the foregoing, a centrifugal machine of automaticbalance type according to the present invention, corrects an unbalancein centrifugal force generated by a load difference of specimens, bymoving horizontally the rotor lever itself or the balance weight member,thereby preventing vibration during centrifugal machining, extendinglife of the centrifugal machine accordingly. Further, the presentinvention not only carries out centrifugal separation of a specimenaccurately, quickly, but also protects a specimen from being destroyed.Still further, as the centrifugal machine informs a user whether thecentrifugal machine can operate within a limited load difference range,a user need not to measure a load of a specimen or adjust the number ofspecimens, whereby operation time necessary for centrifugal machining isreduced.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A centrifugal machine of automatic balance type comprising: at least a rotor lever, to both ends of which a specimen is hooked; a rotor for supporting the rotor lever so that it moves horizontally; a lever moving means mounted within the rotor, for moving horizontally the rotor lever on central line of rotation of the rotor; a load detecting means installed on the rotor lever, for detecting loads weighed on both the ends of the rotor lever; a centrifugal motor for rotating the rotor; an electrical connection means for connecting or disconnecting the load detecting means and the lever moving means to and from an external electrical circuit of the rotor; and a controlling means for controlling the electrical connection mean so as to connect electrically the external electrical circuit to the load detecting means an the lever moving means, for calculating loads weighed on both the ends of the rotor lever by means of a detected signal provided from the load detecting means, and for controlling the lever moving means so that centrifugal forces exerted on both the ends of the rotor lever reach a balance.
 2. The centrifugal machine according to claim 1, wherein the load detecting means is comprised of a strain gauge.
 3. The centrifugal machine according to claim 2, wherein the electrical connection means is comprised of a wiring layer exposed to the rotational shaft of the rotor, with electrically connected to the load detecting means and the lever moving means; a wiring contact plate for coming in contact with the wiring layer only when an external force is applied; and a solenoid for applying or removing a external force to the wiring contact plate.
 4. The centrifugal machine according to claim 3 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load.
 5. The centrifugal machine according to claim 1, wherein the load detecting means is comprised of a pressure sensor.
 6. The centrifugal machine according to claim 5, wherein the electrical connection means is comprised of a wiring layer exposed to the rotational shaft of the rotor, with electrically connected to the load detecting means and the lever moving means; a wiring contact plate for coming in contact with the wiring layer only when an external force is applied; and a solenoid for applying or removing a external force to the wiring contact plate.
 7. The centrifugal machine according claim 6 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as result of calculation of the load.
 8. The centrifugal machine according to claim 1, wherein the lever moving means is comprised of a lever moving motor; a worm connected to the lever moving motor in an axial combining manner; a worm wheel engaged with the worm; a pinion connected to the worm wheel in a coaxial combining manner; and a rack formed lengthwise on the rotor lever, engaged with the pinion.
 9. The centrifugal machine according to claim 8, wherein in case that the rotor lever is two, an intersecting concave groove of a width greater than a width of the rotor lever is formed on an intersecting portion so that rotational plane of each rotor lever lies on the same plane, and the lever moving means is installed in an upper housing and a lower housing of the rotor, respectively.
 10. The centrifugal machine according to claim 9, wherein the electrical connection means is comprised of a wiring layer exposed to the rotational shaft of the rotor, with electrically connected to the load detecting means and the lever moving means; a wiring contact plate for coming in contact with the wiring layer only when an external force is applied; and a solenoid for applying or removing a external force to the wiring contact plate.
 11. The centrifugal machine according to claim 10 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load.
 12. The centrifugal machine according to claim 8, wherein the electrical connection means is comprised of a wiring layer expose to the rotational shaft of the rotor, with electrically connected to the load detecting means and the lever moving means; a wiring contact plate for coming in contact with the wiring layer only when an external force is applied; and a solenoid for applying or removing a external force to the wiring contact plate.
 13. The centrifugal machine according claim 12 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load.
 14. The centrifugal machine according to claim 1, wherein the electrical connection means is comprised of a wiring layer exposed to the rotational shaft of the rotor, with electrically connected to the load detecting means and the lever moving means; a wiring contact plate for coming in contact with the wiring layer only when an external force is applied; and a solenoid for applying or removing a external force to the wiring contact plate.
 15. The centrifugal machine according to claim 14 further comprising: a displaying means for giving a warning in case that a load difference between both the ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load.
 16. A centrifugal machine of automatic balance type comprising: at least a rotor lever on both ends of which a specimen is mounted; a rotor to which the rotor lever is fixed; a balance weight member installed on a center portion of the rotor lever, for being able to move horizontally; a weight member moving means mounted within the rotor, for moving horizontally the balance weight member on a central line of rotation of the rotor; a load detecting means installed on the rotor lever, for detecting loads weighted on both the ends of the rotor lever; a centrifugal motor for rotating the rotor; an electrical connection means for connecting or disconnecting the load detecting means and the weight member moving means to and from an external electrical circuit of the rotor; and a controlling means for controlling the electrical connection mean so as to connect electrically the external electrical circuit to the load detecting mean and the weight member moving means, for calculating loads weighed on both the end of the rotor lever by means of a detected signal provided from the load detecting means, and for controlling the weight member moving means so that centrifugal forces exerted on both the ends of the rotor lever reach a balance.
 17. The centrifugal machine according to claim 16, wherein the weight member moving means is comprised of a weight member moving motor; a worm connected to the weight member moving motor in an axial combining manner; a worm wheel engaged with the worm; a pinion connected to the worm wheel in a coaxial combining manner; and a rack formed lengthwise on the balance weight member, engaged with the pinion.
 18. The centrifugal machine according to claim 17 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load.
 19. The centrifugal machine according to claim 16 further comprising: a displaying means for giving a warning in case that a load difference between both ends of the rotor lever exceeds a predetermined value, wherein the controlling means drives the displaying means in case that the load difference exceeds the predetermined value as a result of calculation of the load. 